The new Manchester United manager, Louis van Gaal, has warned supporters not to expect an immediate turnaround in the wake of David Moyes’ departure, because it will take his players three months to adapt to his new philosophy.

United need a rapid boost in confidence to put last season behind them and, though Van Gaal is blessed with a relatively straightforward early fixture list, he admitted he was asking the players to change to his more technical, tactical game. “It is difficult at first [for players to learn my philosophy] and in the first three months it takes time,” he said. “When we survive the first three months, it will be the same as for me at it was at Bayern in 2009-10. After the first three months there, we were seventh and we were third in the Champions League [group].”

Van Gaal’s Barcelona team were second and 10th after 14 games in his first two seasons there from 1997 and the Ajax team he took over in 1991 secured only 20 points from 16 games. But the Spanish sides won the titles in those seasons, as did Bayern, who also reached the 2009-10 Champions League final.

United play all three promoted sides, Burnley, Queen’s Park Rangers and Leicester City, as well as Swansea City and Sunderland, in the first month of the season and the going only gets tough in October, when the top sides are in Europe. But Van Gaal’s slow starts to campaigns have also brought him sackings in the past – in the first season of his second Barcelona spell in 2002-03 and his second season at Bayern in 2010-11.

Van Gaal said that Manchester City rising from their position as a small club to Premier League champions would help United. “Their success does not bother me,” he said. “Whether they are 10 metres away or 30km away. What they have done is amazing because they were not a big club and now already champions.

“They are knocking at the door but that is good for Manchester United also, because where there is competition you can be proud when you are the champion at the end – and maybe we will be the champions.”

Tourists are limp, leaderless and distinctly UnAustralian

Andrew Grice: Inside Westminster

Blairites be warned, this could be the moment Labour turns into Syriza

The mystery of Britain's worst naval disaster is finally solved - 271 years later

Exclusive: David Keys reveals the research that finally explains why HMS Victory went down with the loss of 1,100 lives

'I saw people so injured you couldn't tell if they were dead or alive'

Nagasaki survivors on why Japan must not abandon its post-war pacifism

The voter Obama tried hardest to keep onside

Outgoing The Daily Show host, Jon Stewart, became the voice of Democrats who felt the President had failed to deliver on his ‘Yes We Can’ slogan. Tim Walker charts the ups and downs of their 10-year relationship on screen